Saito casually mentions that he has a wife to Kenshin and Misao (the manga puts in a "Not Making This Up" Disclaimer). The latter two promptly discuss what kind of woman would marry him. A Buddha is mentioned. Cue Imagine Spot.
During the Shishio arc. Kenshin purposely walked around carrying a sword to avoid contact with other people. Then a flatfoot cop chases him... all day.
A post-Shishio arc Filler episode is a Crowning Episode of Funny. An episode's worth of Hilarity Ensues, all from an engagement ring.
Talking about Filler, what about that time the crew visited a spa...
From both Anime and Manga, there's Kenshin and crew's reaction to Saitou's offhand comment about being married.
In Shin Kyoto Hen, Shishio notices that Kenshin brought a woman along and says that Shingetsu Village's springs are good for healing wounds as well as getting women to open up down there. Misao, said woman, was not amused.
At the start of the Jinchuu Arc, Enishi dubs the group the Six Comrades. Otowa disapproves, and what follows is a short but hilarious argument over what the group should call themselves.